When Paul Kirk is sworn in Friday, he’ll become the sixth unelected member of the current Senate.

And by Russ Feingold’s math, that’s about six too many.

“People shouldn’t be voting in the United States Senate unless they’ve been elected by the people,” Feingold — a Democrat elected three times by the people of Wisconsin — said Thursday as Massachusetts Gov. Deval Patrick named Kirk as a temporary replacement for the late Ted Kennedy.

Feingold wants to amend the Constitution so that all Senate vacancies are filled by special elections rather than by gubernatorial appointments. But until that happens, the 17th Amendment allows states to let their governors appoint replacements — and that means that Roland Burris (D-Ill.), Michael Bennet (D-Colo.), Kirsten Gillibrand (D-N.Y.), Ted Kaufman (D-Del.), George LeMieux (R-Fla.) and, soon, Paul Kirk will be representing constituents who never had a chance to vote for or against them.

“Whether it has to do with closeness or admiration or political considerations, the idea that one person gets to decide rather than all the people in the state bothers me,” Feingold said.

He’s not the only one unhappy with the onslaught of the unelected.

“It’s a problem,” Sen. Lamar Alexander (R-Tenn.), No. 3 in Republican leadership, said of caretakers in particular. “The temporary nature of this is causing me to rethink the whole process. ... The large number of temporary appointments is raising the question that we ought to deal with it one way or another — either the states should or we should.”

Of course, Alexander has a reason to complain: Of the six — counting Kirk — unelected members of the current Senate, five are Democrats, appointed by Democratic governors. And for party leaders, caretakers — or appointed senators who don’t run in the next election — can be loyal votes, hewing to party orthodoxy since they don’t have to worry about carving out a unique image ahead of a political campaign back home. Other than Gillibrand and Bennet, the rest of the appointees are not running for election next year.

Kaufman, who served as an aide to then-Delaware Sen. Joe Biden for 22 years before getting his seat when Biden was elected vice president, has voted with his party 96.5 percent of the time this year, according to a Washington Post database. LeMieux, who was Gov. Charlie Crist’s closest political adviser before Crist tapped him Sept. 9 to fill Mel Martinez’s Senate seat, has voted with Republicans on nearly every vote he has cast so far. And Burris has voted with his party 97 percent of the time, one of the highest party-matching percentages in the Senate today.

“That means that Democrats are siding with Roland Burris [97] percent of the time,” said Burris, who was appointed in December by now-indicted former Gov. Rod Blagojevich to fill President Barack Obama’s old Senate seat.

Kaufman said he is a “very partisan Democrat,” which accounted for his high party unity score, but he also said he brought unique qualifications that made him well-prepared to transition to the job: a Senate aide for more than two decades and teaching courses on Congress at Duke University for 19 years.

“Hitting the ground running is really very, very important,” Kaufman said. “If I’m the governor and I want something done in my state, and I have to call my congressional delegation and get it done — my two senators — I think I would really like two senators who know their way around. .... You want someone there who can represent the citizens of the state.”

Kaufman added that he’s helping carry out what Delaware voters wanted last November: They elected Biden to a sixth Senate term, and Kaufman was his closest adviser. Kaufman plans to sit out next year’s elections, in which Biden’s son Beau most likely will be a candidate.

Crist’s selection of LeMieux, the 40-year-old who now represents Florida, drew fierce criticism by the governor’s GOP primary opponent and his Democratic adversaries since Crist himself is seeking the Senate seat next year.

But LeMieux, who has known Crist since the mid-1990s, said he’s not feeling pressure to vote in ways that will make Crist look good politically.

“I’m my own man,” LeMieux said. “And I’m going to do things the way that I believe are in the best interests of the people of Florida.”

Although Sen. Tom Coburn (R-Okla.) believes that states should have the right to allow gubernatorial appointments, he said that they can create “a negative image of cronyism at the state level — not of Congress.”

In announcing his decision to name Kirk, Patrick downplayed the importance of the Kennedy’s family support for the 71-year-old former Democratic National Committee chairman.

“There are lots of factors that go into a choice like this,” Patrick said, while adding that Kirk had a “special kinship” to Kennedy and would carry on the late senator’s “mission” and “life work.”

But hovering over Kirk’s appointment will be the fact that in 2004, Democrats in the state Legislature took away Republican Gov. Mitt Romney’s power to name an interim appointment if Sen. John Kerry beat President George W. Bush in the election.

Now, Patrick says, “there are vital interests of the people of the Commonwealth that are in the Congress today” that necessitate a second senator before a special election is held in the coming months.

And that has fueled GOP attacks. Senate Minority Leader Mitch McConnell said in an interview that he doesn’t favor having the federal government forcing states to hold special elections. Still, he said he had a suggestion for Democratic lawmakers in Massachusetts: “They should have written a law this way: If there’s a Republican governor, there’s no appointment. And if there’s a Democratic governor, there is an appointment.”